As electric vehicles become more popular and more prevalent, infrastructure is being developed and deployed to charge such electric vehicles. Electric vehicle supply equipment (“EVSE”) can include electric vehicle charging stations used by vehicle owners (e.g., in an owner's garage), charging stations deployed by retailers (e.g., at gas stations and drug stores), and more sophisticated charging stations used by automobile service stations and dealers.
The Society of Automotive Engineers (“SAE”) has promulgated recommendations specifying the electrical characteristics and protocols to promote uniformity in EVSE and encourage wider deployment. For example the recommendation SAE J1772, specifies that Level 1 alternating current (“AC”) EVSE support electric vehicle charging at 120 VAC and up to 16 A. Such devices include charging stations in a vehicle owner's garage. A Level 2 AC EVSE supports charging at 240 VAC and up to 80 A. Such a device provides faster charging compared to a Level 1 AC EVSE, and is more common at a retail establishment.
Level 1 and Level 2 chargers also include support for a pilot signal. A pilot signal is a low voltage signal transmitted by the EVSE to the electric vehicle indicating when the EVSE is ready to supply charging power. The pilot signal is acknowledged by the electric vehicle, indicating that the vehicle is ready to receive power. The pilot signal can be carried on a conductor that is included in the cable and plug that also carries the charging power to the vehicle. A separate pin in the plug can be allocated to the pilot signal.
Level 3 AC chargers are faster and more sophisticated than Level 2 chargers. Such devices can charge a vehicle quickly, e.g., on the order of ten to thirty minutes. Level 3 EVSE is most common at dealers and automotive service stations. In addition to being faster, a Level 3 charger can also include a serial data connection between the EVSE and the electric vehicle. Using the serial data connection, an electric vehicle can communicate to the EVSE information about the vehicle, such as the vehicle's make and model. However, the serial connection requires additional hardware and cables. It would be advantageous to extract vehicle information without the added complexity and expense of this additional equipment.